Thursday's ruling by the military judge, Col. Denise R. Lind, leaves open the question of whether Manning will be court-martialed on more serious charges, including violating the Espionage Act and aiding the enemy, The Washington Post said.
The agreement calls for Manning to accept responsibility for having turned over classified information to the online whistle-blower site WikiLeaks, the newspaper said.
If Manning accepts the terms of the agreement, he could be sentenced to 16 years in prison, the Post reported. Legal analysts say the more serious charges would be difficult to prove, the report said.
He could receive a life sentence if convicted on all charges at his military court martial.
Manning, 24, testified at the pretrial hearing Thursday about alleged abuse he suffered while held at the brig at Quantico Marine Corps base from July 2010 until April 2011, CNN reported.
The judge said any new charges against Manning would have to be filed before he could plead to lesser charges, CNN said. Manning's defense lawyers want the time he has served in military confinement counted as time served in his eventual sentence.
Manning was moved from Quantico to the military prison at Fort Leavenworth, Kan., in April 2011.